1. Field of the Invention
The present invention relates to a socket, especially to a socket adapted for electrically connecting an IC (integrated Circuit) package to a printed circuit board and having lower contacts.
2. Description of the Related Art
To electrically connect to a printed circuit board, an IC (integrated Circuit) package usually need a socket disposed between the IC package and the printed circuit board and electrically connecting with the IC package and the printed circuit board, respectively, for transferring signals between the IC package and the printed circuit board.
A BGA (Ball Grid Array) socket is most popular in those sockets, U.S. Pat. No. 6,976,851 discloses such a socket, which usually comprises an insulative housing defining a plurality of passageways through the insulative housing and a plurality of contacts received in the passageways. The contact is formed with a retaining portion retained in the passageway, a contacting portion upwardly extending from the retaining portion to electrically contact with the IC package and a solder portion downwardly extending from the retaining portion to electrically contact with the printed circuit board. This socket can provide a lower impedance and reliably mechanical and electrical performance thereof. However, for customs' requirements, more and more electrical equipments become smaller and thinner, and the socket also needs to follow this trend. But that is a not simple problem for the contact, because the contact must have a contacting portion with certain length to provide enough elasticity and a retaining portion to retain the contact in the insulative housing, and both the two portions will increase a height of the socket.
Hence, an improved socket is required to overcome the disadvantages of the prior art.